Pi 1 pulsations associated with substorms and their conjugate behavior

• Main Authors: Yoshio Kato, Yutaka Tonegawa
• Format: Report
• Language: English
• Published: Faculty of Science, Tohoku University 1987
• Subjects: Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=2155; http://id.nii.ac.jp/1291/00002155/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=2155&item_no=1&attribute_id=18&file_no=1

Short period geomagnetic pulsations associated with substorms in the frequency range from about 0.1 to 0.4Hz are investigated using the dynamic spectrum analysis technique, and it was found that these Pi 1 pulsations are excited simultaneously with Pi 2 pulsations and they show a clear conjugate behavior. These results will suggest that Pi 1 pulsations might be ion-cyclotron waves generated in the geomagnetic tail due to a drastic change of geomagnetic field configuration in the course of a substorm.